Orthopedics is a medical subspecialty that treats disorders of the human body related to bones, muscles, ligaments, tendons, and joints, with its current emphasis on the treatment of the bones and joints. The treatment of bone and joint disorders can be generally subclassified into categories including the treatment of bone fractures, joint instability, early stage arthritis, and end stage arthritis. Originally, the treatment of orthopedic conditions had mainly relied on casting and bracing. However, with the advent of new implantable materials and development of better joint replacement prostheses, orthopedics shifted its focus to become increasingly more of a surgical subspecialty. With improved materials, better engineering, and a better understanding of the human body, the practice of orthopedic medicine and biomechanical experimentation have made remarkable progress. The treatment of bone fractures and joint disorders has continually been refined to the present state-of-the-art. The last 40 years have shown a myriad of innovations that have concentrated specifically on developing static mechanical design characteristics and new implantable materials used for fracture treatment and in total joint arthroplasties. These static mechanical design characteristics have been directed to solutions for problems concerning wear, stability, and methods of fixation for the total joint arthroplasties. They have also been utilized to improve the current state of the art concerning fracture treatment.
There have been some attempts to develop applications that utilize nonmechanical forces to augment the treatment of particular orthopedic problems. For example, pulsating electromagnetic field has been used as an adjunct to stimulating bone healing. Biochemical and biomaterial means have been used to alter the milieu at fracture sites and in joints to aid healing and to decelerate disease processes. Others have attempted to utilize magnetic fields in treatment of bone and joint disorders as well. For example, U.S. Pat. No. 4,024,588 to Janssen, et al. describes artificial joints with magnets. U.S. Pat. No. 4,029,091 to Von Bezold et al. discloses a method of applying plates to fractured bones so as to allow limited motions of the bone fragments when subjected to an externally generated electromagnetic force. U.S. Pat. No. 4,322,037 to Esformes et al. suggests a elbow joint including mechanically interlocking joint components with the inclusion of a magnetic force on the joint. U.S. Pat. No. 5,595,563 to Moisdon discloses a method of repositioning body parts through magnetic induction generated by extracorporeal magnetic or electromagnetic devices. U.S. Pat. No. 5,879,386 to Jore describes an apparatus to hold bones apart which can also be adjustable from inside the joint, possibly through arthroscopic means. The disclosed devices and methods had only limited uses for specific orthopedic problems. However, these designs are generally not practically feasible due to errors or misconceptions related to the practical application of orthopedic surgical treatments or, more importantly, a lack of understanding concerning the properties of permanent magnets in relationship to the mechanical environment found in the human body, especially as they relate to the normal functions of bones and joints. Accordingly, there remains a need in the art for improved apparatus and methods for less invasively locating and restraining bones in treatment of orthopedic conditions.